Treatment of arsenic-contaminated groundwater with a scrap iron-based electrocoagulation system: human health risk assessment and cost analysis

In this study, we investigated the impact of applied current, charge loading, initial pH, EC time, and packed-bed reactor density on total arsenic removal from groundwater (GW) in a scrap iron-based batch electrocoagulation (EC) process. The best operating conditions to achieve over 93% total arsenic removal for GW₁ and GW₂ were identified as follows: i = 50 mA, q = 1.25 C/L (7.77 F/m³), pH = 7.6, m_b = 40 g Fe/L, and t_EC = 10 min for GW₁; and i = 100 mA, q = 5.0 C/L (3.1 F/m³), pH = 7.1, m_b = 40 g Fe/L, and t_EC = 25 min for GW₂. GW treated with the EC process shows that arsenic does not pose a risk to humans and does not increase the likelihood of cancer, as demonstrated by chronic daily intake (CDI), hazard quotient (HQ), and carcinogenic risk (CR) analyses. The sludge produced after the EC process was examined using Scanning Electron Microscopy (SEM), which revealed a dense and porous structure. Energy Dispersive X-ray (EDX) analysis confirmed effective treatment, as evidenced by the accumulation of arsenic and iron. Furthermore, a comprehensive evaluation was conducted to assess the arsenic removal capacity, energy consumption, total operating costs, and kinetic analysis. The results show that the EC reactor using scrap iron is a reliable approach for treating GW contaminated with arsenic.